[pmwiki-devel] pmwiki licensing: AGPL option?

[Petko Yotov]

On Tuesday 01 March 2011 04:09:12 John Rankin wrote:
> On 1/03/11 12:47 PM, Patrick R. Michaud wrote:
> > On the other hand, my reading of the FSF documents is that the
> > source code your site would offer for download (containing
> > PmWiki + PublishPDF + other components) could be licensed
> > under the AGPL, even while PmWiki itself remains GPLv2.
> > This is possible because PmWiki's license contains the
> > "or any later version" clause of the GPLv2, which means that
> > it can be treated like a GPLv3-licensed package and
> > thereby be compatible with AGPL software.
> 
> Ah, I had not interpreted it that way, but I think you may well be
> right. If it's
> OK to release pmwiki + our extensions in their entirety under the AGPL,
> even though individual components are licensed under the GPL, then that
> meets our requirement.

Correct. PmWiki can be dustributed under the GPLv3. GPLv3 and AGPLv3 software 
are mutually compatible, i.e. you can combine them in larger packages. When 
you combine them, even if GPLv3 components remain GPLv3, you have to "convey" 
the combined source of both the AGPLv3 and GPLv3 parts.

> So the "or any later version" clause means we can choose to take the
> pmwiki source under the AGPL, without pmwiki being explicitly offered
> under the AGPL.
...
> It's more that I had not understood the wording "or any later version"
> can be
> applied to licences other than the GPL, and in particular to the AGPL.
> So we can
> choose the AGPL, even though pmwiki does not explicitly offer it.

Not exactly. The PmWiki source code will remain GPLv3, but this license allows 
the "combination" with or incorporation in AGPLv3 code, so this combination is 
legally possible. 

The Section 13 of both licenses refers to the combined works.

  http://www.gnu.org/licenses/gpl.html#section13
  http://www.gnu.org/licenses/agpl.html#section13

Petko